SPOILER LEVEL: Medium
I loved the original short novel version of this in the Mirror Universe collection Glass Empires, so I was willing to give this expanded version a try. I'm very glad I did. Besides still being a compelling read, I think it fleshes Emperor Spock out in a much needed way. I remember after the first version came out, people were saying on the Psi-Phi boards that it seemed too cruel of Spock to deliberately allow the Empire to fall. I disagreed because this wasn't our universe's Spock, this was the Mirror Spock we were talking about, who came from a brutal universe. And this version shows it very well, as Emperor Spock does some very brutal things for what he believes will be for the greater good of the galaxy as a whole.
Personally, I love the idea that everything we've seen in the DS9 Mirror Universe has all been part of Spock's "Seldon Plan." I really hope David Mack gets the opportunity to expand on this and write the second book he wants to write to show how it will all come together.